The present invention relates to a liquid crystal display technology, and more particularly to an optical alignment device for a plurality of liquid crystal display panels.
PSVA (polymer stabilized vertical alignment) is a technology for producing a TFT-LCD (thin film transistor-liquid crystal display). Liquid crystals in the liquid crystal display panels comprise reactive monomers which can be activated by UV irradiation, so as to form a pretilt angle of the liquid crystals. The abovementioned process is called UV optical alignment.
In the UV optical alignment, the pretilt angle of the liquid crystals directly influences optical properties of the panel. When the pretilt angle is too small, the response time is too slow; when the pretilt angle is too large, the contrast of the panel is too low. The influence factors of the pretilt angle comprise UV intensity, UV irradiation time, the total amount of the UV irradiation, and temperature.
Currently, the liquid crystal display panel is produced by a process for a large size panel. That is, a piece of large size panel can be divided into a plurality of panels. The panels should generally be the same size for integrating the design and manufacturing flow. According to the abovementioned principle, it is possible to leave a lot of area on the substrate after the arrangement of certain size panels is finished, and thus the substrate utilization is lower. Therefore, an MMG (multimodel glass) product is developed. On the MMG substrate, the panels having different sizes can be arranged so that the area remaining on the substrate can be decreased to improve the substrate utilization.
However, the UV irradiation on the MMG substrate always has a uniform intensity, but the aperture ratios or the transmittances of the panels having different sizes are possibly different from each other, which may cause various dimensional panels to receive different UV intensities and form the different pretilt angles, so that pretilt angles of the liquid crystals in a portion of the panels cannot reach to standard.
It is therefore necessary to provide an optical alignment device for a plurality of liquid crystal display panels to solve the problems existing in the conventional technology as described above.